Motor fuels



Patented July 19, 1938 UNITED STATES MOTOR FUELS Leroy G. Story, Beacon, N. 1,, asaignor to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing.

Application September 2, 1932,

Serlal. No. 631,498

1 Claim.

This invention relates to motor fuels and has to do particularly with the provision in the fuel of a gum inhibitor or antioxidant.

An object of the invention is to produce an improved fuel for internal combustion engines.

An important object of the invention is to treat unstable hydrocarbon oils, such as cracked gasolines, which normally tend to deteriorate on standing, with an inhibitor adapted to inhibit gum formation therein and to prevent loss in color and anti-knock property.

Another object of the invention is to produce an improved gum inhibitor from by-products produced in and recoverable from petroleum oils.

Gum inhibitors have been used heretofore in cracked gasolines and various compounds have been proposed in the prior art for this purpose. Such materials, in general, have consisted of synthetic organic compounds which are often relatively insoluble in the gasoline and usually rather expensive.

In accordance with the present invention, instead of using well known chemical compounds that may have anti-oxidant properties when added to cracked gasoline, I contemplate obtaining gum inhibitors from petroleum itself. I have found that a small amount of bodies capable of exhibiting mild antioxidant properties are present in certain oils, particularly cracked naphthas. Such materials are of phenolic character-and are described and claimed as gum inhibitors for gasoline in a copending application of Johan C. C. Oosterhout, Serial No. 625,547, filed July- 28, 1932. The present invention has to do with the conversion of these phenolic bodies occurring in certain oils and recoverable as byproducts therefrom into inhibitors which. are more effective than and have certain other advantages over the raw materials.

The petroleum phenols are produced chiefly in cracked naphthas. They are readily extracted amino or hydroxyl group on the benzene ring, al-,

though, of course, one or more of each may be substituted into the original compounds. The method of converting the phenolic bodies into amino or hydroxy derivatives is described in the literature and may be carried out in accordance therewith by one skilled in the art. A convenient method of introducing an amino group is to nitrate the raw material and then reduce the nitro compound to the corresponding amino derivative by suitable reducing agents. An hydroxyl group may be substituted into the molecule by sulfonation and then replacementpf the sulfonic radical with an hydroxyl radical by caustic fusion. The number of amino or hydroxyl-radicals introduced may be controlled by varying the operating conditions.

The phenolic compounds may be treated as just described in the purified or crude form, but I prefer to subject them before treatment to a purification treatment, such as fractional distillation. Sometimes it is advantageous to treat the materials in the'vapor phase with a decolorizing or desulfurizing agent; and, accordingly, the vapors may be contacted with fullers earth, copper oxide, charcoahetc. or mixtures thereof. The purified material should be free from dimcultly volatile and gum-forming constituents. While the boiling range may vary within quite wide limits, a suitable range has been found to be of the order of about 150 C. to 300 C.

According to one aspect of the invention the phenolic compounds recovered from a cracked naphtha may be reused in the same naphtha to inhibit gum formation. In this manner an oil containing oxygenated compounds is subjected to any well known or preferred liquid or vapor phase cracking system whereby high boiling hydrocarbons are converted into low boiling hydrocarbons and. simultaneously oxygenated compounds present may be converted into phenolic bodies; or a naphtha of low anti-knock value may be subjected to a reforming operation to increase the anti-knock property and at the same time phenols may be produced as a result of the decomposition of the oxygenated compounds. The cracked or reformed naphtha may be refined in the usual way with acids, filtering agents, etc., including alkali or doctor treatment, whereby the phenols are removed. The phenols may then be recovered from the alkaline reagent by acidifying the solution or passing carbon dioxide therethrough to liberate the phenolic compounds which may then be separated by stratification and decantation. The recovered phenolic bodies, with or without preliminary purification, as described heretofore, may be converted into suitable amino or polyhydrozw derivatives and the resultin8 derivatives addedagain to the finished gasoline or naphtha to eifect stabilization thereof.

The quantity of inhibitor required to be used is usually very small. Although the quantity may vary somewhat it may be said that 0.005% to 0.025% is satisfactory forpractically all gasolines and preferably, a quantity of the order of 0.01% by weight.

The inhibitors are usually quite soluble in gasoline due to the presence in the original phenolic compounds of hydrocarbon side chains which bear some relationship in composition to the gasoline from which they are recovered. For that reason they may be readily dissolved in the oil to any extent simply by agitating thematerial with the oil, or other suitable means of contact. However, it may be desirable in some cases to use a mutual solvent, such as acetone, benzol, etc. Thus the inhibitor may be dissolved in the solvent and the solution dispersed in the gasoline.

As an example of the operation of my invention, phenolic compounds recovered from a cracked naphtha resulting from cracking Mid- Continent gas oil were purified by distillation to obtain a product having a boiling range of about 190 C.-215' C. and a gravity of 1.030 at 15' C. This material was nitrated in the usual manner and the resulting nitrated product reduced to the corresponding amino derivatives. About 0.01% of the amino compounds was added to a gasoline showing, without treatment, a gum content of 108 mg. per cc. by the Copper Dish Method of test. The treated product. by the same test, showed about 10 mg. per 100 cc.

The Copper Dish Method referred to above is that of the Bureau of es, Method 530.1, as described in Technical Paper 323-3, of the U. B. Department of Commerce.

Obviously many modifications. and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claim.

I claim:

In' the treatment of cracked hydrocarbon distillates of the type obtained by cracking hydrocarbons which produce substantial quantities of phenolic substances in the cracked distillate, the steps of extracting the phenolic substances from the cracked distillate, subjecting the phenolic extract to fractional distillation thereby obtaining a fraction having improved inhibitor action, converting the phenolic compounds of said fraction into more highly eflective inhibitor bodies of the class of polyhydroxy and aminohydroxy phenols by introducing into said phenols additional substituents of the class of amino and hydroxy, and re-adding said more highly effective inhibitor bodies to the distillate in suflicient quantity to substantially stabilize said distillate against gum formation.

LEROY G. STORY. 

